Lead-zirconate-titanate (PZT)-based ceramics have been the primary material used in piezoelectric devices over the past several decades, especially in piezoelectric devices such as ultrasound medical probes, hydrophones and sonar for underwater imaging and communications, multi-layer actuators for fuel injection, piezoelectric printers etc. To enhance the piezoelectric properties of PZT ceramics, compositions near a phase transition are chosen.
In this regard, single crystals of solid solutions of lead-zinc-niobate and lead-titanate (PZN-PT) and of lead magnesium-niobate and lead-titanate (PMN-PT) are promising new materials. Compared to the conventional state-of-the-art PZT ceramics, PZN-PT and PMN-PT single crystals have significantly large electromechanical coupling (conversion of energy from electrical to mechanical and vice-versa) due to the much higher values of piezoelectric coefficients (about 4-5 times that of PZT), to offer advantages over the older standards.
Notwithstanding the advantages offered by newer piezoelectric materials such as PZN-PT and PMN-PT, there remains a desire to have further new piezoelectric materials with unique and advantageous characteristics, e.g. materials with piezoelectric coefficients which are significantly higher than those obtained with currently available materials.